Japanese UM Publication No. 72485/81 discloses an electrical connector having a retention feature in which the posts have outwardly extending projections that have been formed by compressing parts of the side surfaces upon insertion of the terminals into a board, the projections provide force against the sidewalls of a through-hole of a circuit board to secure electrical connector to the board during the soldering process. As is known in the art, compressed or coined areas are typically formed during the terminal stamping process by applying force from opposed directions to flatten the selected areas. Since force needs to be applied from both sides of the terminal, the coined area is generally formed prior to insertion of the terminals into the housing, particularly if the coined terminals are being used in a multi-row connector. The coined terminals are then placed in the housing at selected locations to provide a desired amount of retention force. Depending upon the dimension of the coined area, the connector may be secured to the board by interference fit of one or more individual terminals or by two or more terminals that cooperate with one another. Assembly of a connector of this type is labor intensive, in that the coined terminals need to be individually loaded, into the housing at selected locations. It is desirable, therefore, to provide electrical connector wherein retention means can be provided by a post connector assembly operation.
The amount of force necessary to coin a terminal depends upon the thickness or stiffness of the material. In addition, when coined areas are applied to relatively stiff posts such as posts having cross sectional dimensions of 0.025 .times. 0.025 inches, problems have been encountered owing to the fact that the through-hole geometry of the circuit board varies within a range of tolerances, and the retentive coined feature must function properly throughout the range. If the terminal is held in the hole with an interference fit, the force required to insert a connector into the minimum size holes within the tolerance range may be extremely high relative to the force for the nominal or maximum size holes of the range. Conversely, if the force is not sufficient, the terminals will not be sufficiently secure within the maximum size hole to hold the connector to the board during wave or other soldering process.